Dapper Sound System broken by plugging in a Webcam

[Sven Herzberg]

I bought a webcam some time ago, now I attached it to my computer and it works fine. But there's a really big problem for me right now.

As both the webcam and the sound card of the computer are accessed by alsa, I have two alsa devices: hw:0 and hw:1

Unfortunately the assignment of these devices seems to change with every reboot (I didn't check this behaviour, but I have the feeling that one day it works and one day it doesn't).

So, please provide a solution for

a) keeping the sequence of detetion the same with every reboot
b) provide a way to specify the alsa device for the gstreamer alsa sink by something different than the "hw:0" name

[Sven Herzberg (herzi)]

Changing to major as this makes listening music not really user friendly.

[Sebastien Bacher (seb128)]

reassigning to alsa, gst doesn't decide of the devices order

[Hasta Manana (manhasta)]

I can confirm this bug. Computers with more than one sound card (in my case ESI Juli@ and SAA1734) get random sound device list order. This is extremely annoying. I had to come up with this to make sound on my tv-tuner to work:

sox -r 32000 -w -t ossdsp /dev/dsp`arecord -l | grep '^card [0-9]: SAA7134' | awk '$2 == "2:" {print "2"}'` -t ossdsp /dev/dsp`aplay -l | grep '^card [0-9]: Juli \[ESI Juli@\], device 0:' | awk '$2 == "2:" {print "2"}'`

because sound devices interchange between /dev/dsp and /dev/dsp2 randomly at reboot. Also, it affects the 'Default sound card' setting in sound preferences.

[Daniel T Chen (crimsun)]

(Dropping Importance. Sorry, but a usability bug, while extremely annoying, does not constitute an Importance of the extremity of a system crash.)

If System> Preferences> Sound> Default sound card's drop-down menu is not working properly, that's a bug in the gnome-control-center source package.

alsa-utils in Dapper includes the asoundconf(1) utility that gnome-control-center's Sound applet invokes to perform the background task. If you find using asoundconf(1) [see the set-default-card convenience macro] remains utterly ineffectual, then you can forcibly set one driver to /not/ be the default (i.e., not grab index 0).

Let's take the example of my computer, which uses the snd_intel8x0 and snd_usb_audio drivers. (While asoundconf(1) works for me, for the purposes of this illustration I'll pretend it doesn't work.) Let's say that I really want my onboard sound chipset to be the secondary instead of the primary, since my M-Audio Transit USB is a "much better"/preferable device. In this case I would issue the following command:

$ echo "options snd_intel8x0 index=-2" |sudo tee -a /etc/modprobe.d/alsa-base

The above command effectively forces the snd_intel8x0 driver to not grab the first available index in the presence of other drivers.

So -- what info is needed for you guys? Please /attach/ (don't comment inline) the output from ``lspci -v && cat /proc/asound/cards''. Also indicate which of the cards you wish to use as the primary one and whether asoundconf(1) [with the convenience macro mentioned above] works when you invoke it by hand and restart ALSA apps (this does not affect OSS emulation).

[Sven Herzberg (herzi)]

I cannot agree here. The "solution" that you explain here is a workaround, but I consider needing to fix this problem manually still a bug in Ubuntu.

[Daniel T Chen (crimsun)]

I'm not disagreeing that it's a bug (and even stated as much in my reply); I've encountered it myself using the System> Preferences> Sound control panel. I'm saying the workaround described above is viable until the developers have more time to troubleshoot.

[Martin Pitt (pitti)]

Hi,

Daniel T Chen [2006-06-17 19:03 -0000]:
> If System> Preferences> Sound> Default sound card's drop-down menu is
> not working properly, that's a bug in the gnome-control-center source
> package.

That was not stated by the reporter. I assume that the original
reporter never used this function in the first place. As soon as you
select a default card in the applet, then the default ALSA card will
be fixed (by setting it in ~/.asoundrc.asoundconf).

So, a random hotplug order is not something we can change, at least in
the short time. Instead, we could write a default .asoundrc in a login
session if none exists yet.

Martin

--
Martin Pitt http://www.piware.de
Ubuntu Developer http://www.ubuntulinux.org
Debian Developer http://www.debian.org

[Daniel T Chen (crimsun)]

There is now (as of Dapper) a system in place to use the more human-friendly string from ``asoundconf list''. Using asoundconf(1)'s convenience macro, set-default-card, will write an ~/.asoundrc.asoundconf that is resilient to changing device indices.

Please report whether it works in Dapper. If it doesn't, please try today's Edgy live cd.

[Daniel T Chen (crimsun)]

Fixed in Edgy. (Note this change makes people who want to use usb audio devices by default as card 0 unhappy.)